Dissertations / Theses on the topic 'Lipid degradation'
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Amir, Alipour Mohsen. "Effect of EPA on Intercellular Lipid Droplets Degradation." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36108.
Full textAsano, Lisa. "Vitamin D metabolite, 25-Hydroxyvitamin D, regulates lipid metabolism by inducing degradation of SREBP/SCAP." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225512.
Full textLee, Yoon-Hee. "Effect of Riboflavin and Lumichrome Degradation on the Oxidative Stability of Salad Dressing." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1253631242.
Full textTipsrisukond, Narin. "Impact of lipid degradation processes, and supercritical carbon dioxide extraction on flavor characteristics of lard /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p3091972.
Full textCarbone, David L. "Effects of the lipid peroxidation product 4-hydroxy-2-nonenal on protein degradation and refolding pathways /." Connect to full text via ProQuest. IP filtered, 2005.
Find full textSato, Shin. "Degradation of cis-1,4-polyisoprene rubbers by white rot fungi and manganese peroxidase-catalyzed lipid peroxidation." Kyoto University, 2005. http://hdl.handle.net/2433/78163.
Full text0048
新制・課程博士
博士(農学)
甲第11635号
農博第1491号
新制||農||908(附属図書館)
学位論文||H17||N4028(農学部図書室)
UT51-2005-D384
京都大学大学院農学研究科応用生命科学専攻
(主査)教授 渡邊 隆司, 教授 島田 幹夫, 教授 東 順一
学位規則第4条第1項該当
Zahoor, Muhammad kashif. "Genome wide analysis for novel regulators of growth and lipid metabolism in drosophila melanogaster." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00664844.
Full textRuggiano, Annamaria 1985. "Control of endoplasmatic reticulum homeostasis by Doa10-dependent protein degradation." Doctoral thesis, Universitat Pompeu Fabra, 2015. http://hdl.handle.net/10803/384851.
Full textThe function, shape and identity of cellular organelles are too a large extent determined by their lipid and protein composition. In order to maintain cellular homeostasis, the rate of synthesis and degradation of proteins and lipids must be accurately controlled. Proteolysis by the ubiquitin-proteasome system plays a major role in regulating the half-lives of a range of proteins. A multitude of cellular processes depends on timely controlled and selective protein degradation; just to mention a few, these include intracellular trafficking and secretion, elimination of damaged polypeptides and DNA repair. Remarkably, anomalies in the ubiquitin-proteasome system have been linked to several human pathologies. Misfolded proteins in the membrane and lumen of the endoplasmic reticulum (ER) are constitutively generated during protein biosynthesis. These species are potentially toxic and are eliminated by the ubiquitin-proteasome system through a quality control pathway called ER-associated protein degradation (ERAD). Beyond this well-studied role, ERAD controls the levels of some folded, functional but short-lived ER proteins by eliminating them under a specific physiological condition, thereby in a regulated fashion. Of note, sterol production is adjusted to cell needs through feedback control of the HMGR enzyme stability. Despite its importance in ER homeostasis, regulated degradation through ERAD still accounts for only few examples. Yeast Doa10 is one of three ER ubiquitin ligase enzymes implicated in the degradation of misfolded proteins. To seek for regulated Doa10 clients, we pursued a proteomics screening. We identified potential targets involved in diverse cellular functions and further characterized some of them. We demonstrate that Doa10-dependent degradation critically impacts lipid homeostasis through regulated disposal of the sterol pathway enzyme Erg1. Moreover, we show that Doa10 mediates degradation of proteins belonging to lipid droplets, an ER-derived organelle; this finding highlights a role for ERAD in protein spatial control and maintenance of ER identity.
Schwab, Martin. "Degradation of lipid based drug delivery systems and characterization of semi-synthetic spider silk proteins for the application in pharmaceutical technology." Diss., Ludwig-Maximilians-Universität München, 2009. http://nbn-resolving.de/urn:nbn:de:bvb:19-165238.
Full textMaheshwari, Neeraj. "Biofuntionalisation of PLGA based polymer nanoparticles for vectorization : interaction with biomimetic lipid membranes and bio-controlled release." Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2357.
Full textThis thesis aims at developing PLGA nanoparticles for controlled release and investigating its interaction with phospholipid bilayers mimicking cell membranes. For passive controlled release the physiochemical changes were monitored by incubating the PLGA (50:50) NPs in different buffered pH conditions at increased time intervals. PLGA exhibited dissimilar degradation behavior with pore formation for high pH (basic conditions) maintaining the volume of the particles but change in the density, while at low pH it showed surface erosion. There is decrease in the particle size upon incubating in low pH. This study was carried out using DLS, ESEM and spectrophotometry. For active release the walls of PLGA (75:25) capsules were modulated using phospholipids. The release of hydrophilic fluorescent probe Calcein was monitored with increasing the temperature. It was observed that with DOPC (0.31mM) the release can be triggered using detergents or an enzyme (PLA2). We propose the formation of a lipid-polymer complex within the polymer matrix forming plugs which are vulnerable to enzymes/detergents inducing release. The effect of PLGA NPs over the phospholipid bilayers mimicking cell membrane was carried out using molecular fluorescent probes (Prodan and Laurdan). The study was carried out by calculating the generalised polarisation (GP) under the influence of PLGA NPs (50:50 and 75:25). It is found that the interaction is a surface phenomenon and there is no influence of NPs over the permeability of model membranes LUVs and SUVs. The Tm value of the phospholipids is also maintained when studied with Laurdan. Prodan probe GP studies provide first original method to determine the Tg of PLGA in complete aqueous conditions. It is a rapid and easy method which determines the Tg value of PLGA in real time using very small quantity of the sample. This interaction is not affected by the composition of the bilayer mimicking cell membranes
Schwab, Martin [Verfasser], and Gerhard [Akademischer Betreuer] Winter. "Degradation of lipid based drug delivery systems and characterization of semi-synthetic spider silk proteins for the application in pharmaceutical technology / Martin Schwab. Betreuer: Gerhard Winter." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2014. http://d-nb.info/1046785257/34.
Full textMasarin, Fernando. "Estudo da degradação de lignina iniciada por metabólicos extracelulares extraídos de cultivos de Ceriporiopsis subvermispora." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/97/97131/tde-27092012-111546/.
Full textThe white-rot fungus Ceriporiopsis subvermispora degrades lignin selectively, being one of the most studied species in biopulping. Biopulping consists of a biological treatment of wood that precedes conventional pulping stages. The process can provide up to 30-40% of energy savings in mechanical pulping. To degrade lignin, this fungus secretes the enzyme manganese-peroxidase (MnP), which needs carboxylic acids to chelate and transport Mn3+ ions formed in the catalytic cycle of the enzyme. The chelate-Mn3+ complex is able to degrade phenolic structures of lignin; however, can also initiate lipid peroxidation reactions generating peroxyl radicals that are able to degrade nonphenolic lignin structures. Based on this background, the aim of this work was to evaluate lignin degradation through linoleic acid peroxidation reactions initiated by extracellular metabolites recovered from C. subvermispora cultures. Some biomimetic systems based on Fe2+ and Mn3+ ions were also evaluated as initiators of such reactions. The lignin degradation was studied in reaction systems composed of MnP/Mn+2/H2O2, Fe3+-reducing compounds produced during wood biodegradation by C. subvermispora, Mn+3 or Fe+2 ions, all of them in the presence of linoleic acid. To perform this study, MnP and Fe3+-reducing compounds were initially produced in C. subvermispora cultures. Two different reaction substrates were also prepared. One was a lignin-carbohydrate complex (LCC) and, the other, was a complete lignocellulosic material that was milled and extracted to remove the extractive fraction. Both substrates were prepared from Eucalyptus grandis wood. The chemical characterization of the substrates showed 44.8 % and 29.0 % of total lignin, respectively. Linoleic acid peroxidation reactions initiated by the studied systems showed that all of them were efficient on this purpose. The highest oxygen consumption rates during these reactions were observed in the Fe2+ initiated reactions. The LCC inhibited the peroxidation reactions when added to the reaction medium at concentrations higher than 0.3 mg/mL. However, prolonging the reactions up to 72h with LCC at 1 mg/mL showed that it was depolymerized. The lignin degradation routes involved depolymerization or simple side chain and free-phenolic structure oxidations. When the reactive system was based on the use of MnP/Mn+2/H2O2/linoleic acid, some lignin degradation routes were demonstrated and they included Cα-oxidation, as well as β-O-4 and/or Cα-Cβ cleavages. These results corroborate previous findings published for the action of C. subvermispora in vivo. One exception was the simple Cα oxidation that was observed for the in vitro reactions, but was ruled out by previous works that were based on the characterization of residual lignins extracted from wood samples biotreated by C. subvermispora (in vivo system). The current results permitted to conclude that several mimetic systems were able to initiate linoleic acid peroxidation in vitro. When these reactions were performed in the presence of lignin (LCC or milled E. grandis) it was possible to show the occurrence of several lignin transformation reactions that could be exploited, for example, in pulp bleaching processes.
Hult, Louise. "Fäst vid keramik : En experimentell undersökning av lipidrester i keramik, med GC-MS-metod, efter nedbrytningsförsök." Thesis, Stockholms universitet, Arkeologiska forskningslaboratoriet, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-87173.
Full textJin, Qi. "Effects of Rosemary Extract and Propyl Gallate as Antioxidative Oil Additives and Whey Protein Isolate as an Oil Barrier on Degradation of Oil and Production of Fried Chicken." Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1523653298103237.
Full textBachratá, Radka. "Molecular study of lipids in humic acids by sequential chemical degradation." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2009. http://www.nusl.cz/ntk/nusl-216468.
Full textVlčková, Bohumila. "Testování komerčních přípravků do odlučovačů tuků." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2008. http://www.nusl.cz/ntk/nusl-216440.
Full textau, y. kuang@exchange curtin edu, and Yunhua Kuang. "Enhancing Anaerobic Degradation of Lipids in Wastewater by Addition of Co-substrate." Murdoch University, 2002. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20040820.132229.
Full textDobrzanski, Tatiane. "Sistema de respostas de Bacillus sp. à toxicidade induzida pelo herbicida Callisto e princípio ativo." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2015. http://tede2.uepg.br/jspui/handle/prefix/941.
Full textExcessive use of herbicides for weed control in agriculture causes a selective pressure on soil microbiota and waters near application area, changing environmental balance. Some microorganisms have developed metabolic pathways for degradation of these xenobiotics, although tolerance and degradation processes can generate free radicals and affect survival. This study aimed to analyze the system of responses from soil and water strains, submitted to selective pressure by the herbicide Callisto®. Strains CCT7729 and CCT7730, isolated from soil and water, respectively, were identified as Bacillus sp., and showed different degradation routes, with different metabolites, already described in the literature. Mesotrione and its metabolites, and especially its commercial product Callisto, affected cell viability and altered cell membrane lipids from the tested strains, however, Bacillus sp. CCT7729 presented a more efficient system of responses to oxidative stress. This strain exhibited a greater efficiency to degrade mesotrione, lower rates of peroxide, lower rates of MDA, SOD high activity and low activity of catalase, when compared to Bacillus sp. CCT7730. Changes in membrane lipids can be considered as a defense against oxidative stress strategy. These results indicated the existence from a variety of metabolic pathways for mesotrione degradation to Bacillus sp. Probably metabolites induce different levels of toxicity in bacteria, and Bacillus sp. CCT7730 possibly degraded mesotrione in even harmful compounds, unlike the water line. It is possible that these different responses are related to the home environments of each strain, suggesting plasticity responses of Bacillus sp. for adaptation to toxic substances in different environmental contexts.
O uso intenso de herbicidas para controle de ervas daninhas na agricultura provoca uma pressão seletiva na microbiota do solo e de águas próximas à área de aplicação, alterando o equilíbrio ambiental. Alguns microrganismos apresentam vias metabólicas de degradação desses xenobióticos, entretanto, a tolerância e os processos de degradação podem gerar radicais livres capazes de afetar a sobrevivência. Este trabalho teve como objetivo analisar o sistema de respostas de linhagens provenientes de solo e água, e que foram submetidas a pressão seletiva pelo herbicida Callisto. Uma linhagem isolada de cada um destes ambientes, identificadas respectivamente, como Bacillus sp. CCT7729 e Bacillus sp. CCT7730, apresentaram rotas de degradação diferenciadas, com metabólitos diferentes dos já descritos na literatura. O mesotrione, seus metabólitos, e principalmente o Callisto, afetaram a viabilidade celular das linhagens deste estudo e alteraram os lipídios de membrana celular, no entanto, Bacillus sp. CCT7729 apresentou um sistema de respostas ao estresse oxidativo mais eficiente. Esta linhagem exibiu uma maior eficiência em degradar o mesotrione, menores taxas de peróxido, menores taxas de MDA, atividade SOD elevada e uma baixa atividade da catalase, ao contrário de Bacillus sp. CCT7730. Modificações nos lipídios de membrana podem ser consideradas como uma estratégia de defesa contra estresse oxidativo. Os resultados também indicaram uma diversidade de vias metabólicas nas duas linhagens de Bacillus sp. para a degradação do mesotrione. Provavelmente os metabólitos induziram diferentes níveis de toxicidade nas bactérias, sendo que Bacillus sp. CCT7730 possivelmente degradou o mesotrione em compostos ainda nocivos, ao contrário da linhagem de água. É possível que essas diferentes respostas estejam relacionadas com os ambientes de origem de cada linhagem, sugerindo uma plasticidade de respostas apresentadas por linhagens Bacillus sp. para adaptação a substâncias tóxicas em diferentes contextos ambientais.
Kuang, Yunhua. "Enhancing anaerobic degradation of lipids in wastewater by addition of co-substrate." Thesis, Kuang, Yunhua (2002) Enhancing anaerobic degradation of lipids in wastewater by addition of co-substrate. PhD thesis, Murdoch University, 2002. https://researchrepository.murdoch.edu.au/id/eprint/136/.
Full textKuang, Yunhua. "Enhancing anaerobic degradation of lipids in wastewater by addition of co-substrate." Kuang, Yunhua (2002) Enhancing anaerobic degradation of lipids in wastewater by addition of co-substrate. PhD thesis, Murdoch University, 2002. http://researchrepository.murdoch.edu.au/136/.
Full textCalonne, Maryline. "Impact des hydrocarbures aromatiques polycycliques sur le métabolisme lipidique et le transport du phosphore chez le champignon mycorhizien à arbuscules Rhizophagus irregularis." Thesis, Littoral, 2012. http://www.theses.fr/2012DUNK0311/document.
Full textPolycyclic aromatic hydrocarbons (PAHs) are among the major persistent organic pollutant frequently found in the polluted soils and are harmful for human health and its environment. To clean-up the PAHs polluted soils, phytoremediation assisted by arbuscular mycorrhizal fungi (AMF) could represent an innovative, ecological and cost-effective alternative. The use of mycorrhizas, as phytoremediation tool, has several advantages including increased tolerance to the pollutant toxicity, improved water and mineral nutrition as well as a better pollutant dissipation. Few studies have described the impact of PAHs on the AMF development related with lipid peroxidation and total lipid content disturbance. However, so far neither the target action of these pollutants on the metabolism, nor the role of these lipid changes in PAH tolerance and in their dissipation have been studied. Therefore, the present work aims firstly to improve our understanding of the PAHs impact on the CMA lipid metabolism. Thanks to radiolabeling experiments with [1-¹⁴C] acetate, our results showed a disruption of the membrane lipid biosynthesis pathways in the AMF extraradical mycelium, grown in the presence of PAHs. Secondly, it was highlighted that the PAHs affectef the phosphate nutrition. Finally, the mycorrhizas abilities to degrade and to bioaccumulate the benzo[a]pyrene, were pointed out. The involvement of extraradical mycelium storage lipid (triacyglycerols) metabolism in the membrane regeneration, the fight against the PAH induced-oxidative stress and the PAH metabolism/bioaccumulation is discussed
Bröder, Lisa-Marie. "Transport, degradation and burial of organic matter released from permafrost to the East Siberian Arctic Shelf." Doctoral thesis, Stockholms universitet, Institutionen för miljövetenskap och analytisk kemi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-136380.
Full textAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 4: Manuscript.
Santos, Carla Cristina (Lucas Kyem) Araújo dos. "Tratamento de efluente de laticínio em reator anaeróbio compartimentado." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/74/74132/tde-23082016-093549/.
Full textEffluents with high concentrations of lipids, although demonstrating high potential for methane production represents potential inhibition of the anaerobic consortium activity, depleting the production of biogas. This project was carried out monitoring an anaerobic hybrid baffled reactor with five compartments (ABR) treating simulated dairy wastewater. The biomass, was adapted for 51 days and then subjected to hydraulic retention times (HDT) of 72h, 24h and 12h, resulting in a monitoring period of 340 days. While operating with 24h of HRT, the system was subjected to three organic and hydraulic shock loads, when its HDT was decreased to 12 h. The reactor absorbed the shock within 36 hours, achieving similar efficiencies to the previous condition. Nevertheless, although presenting high organic matter efficiencies, when permanently operating with HDT of 12 h, clogging problems due to biomass flotation were constant. The organic matter removal efficiencies for each operational condition were 92 ± 3%, 91 ± 1.8%, 90 ± 2,4%. Those values were statistically similar. The methane percentage in the biogas increased with the HDT reduction, being 41 ± 23, 53 ± 27, and 62 ± 12% when the HDT were 72, 24 and 12 hours. Alkalinity production was observed since the beginning of operation. The mean relation between intermediate and partial alkalinity was 0.1±0.006 in samples collected in the system output. Although presenting clogging problems with the smallest HDT, the ABR was efficient, robust and reliable when treating dairy effluents, producing a high quality liquid effluent and a methane rich biogas.
Karlsson, Emma. "Compositional clues to sources and sinks of terrestrial organic matter transported to the Eurasian Arctic shelf." Doctoral thesis, Stockholms universitet, Institutionen för miljövetenskap och analytisk kemi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-116876.
Full textAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.
Kuo, Shu-Jung. "Chilling-induced lipid degradation in cucumber fruit (Cucumis sativa L.)." 1989. http://catalog.hathitrust.org/api/volumes/oclc/20051854.html.
Full textTypescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 112-133).
Thiam, Tan Kien, and 陳健添. "β-Adrenergic Receptor-Stimulated Lipolysis Required the Rab7-Mediated Autolysosomal Lipid Degradation." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/4tdf2u.
Full text國防醫學院
生命科學研究所
99
The hormone-stimulated lipolysis is a rapid way to mobilize fat from its storage depot for use in peripheral tissues. The only molecular mechanism considered so far is the activation of cellular lipases by β-adrenergic receptor (β-AR)/cAMP signal pathway to liberate fatty acids from triglycerides that are stored in lipid droplets (LDs) of cells. This study provides evidence showing that autophagy activity contributes in significant part to this stimulated lipolysis. The pharmacological inhibitors and the shRNA-based gene inhibition on the early or late autophagy reduce significantly the stimulated lipolysis. Upon β-AR activation, there is a marked increase in the autophagy-targeted LDs for lysosomal degradation, which is dependent on the LD-associated Rab7. Rab7 is physically interacts with perilipin, and this interaction is significantly enhanced by the β-activation. The dominant negative mutant of Rab7 not only abolishes its association with LDs but also eliminate the recruitment of autophagic components to LDs during the β-AR activation.
Ding, Haibing. "Study of biogeochemical factors affecting organic matter (lipid biomarkers) degradation structural association, redox condition, enzymatic response, and benthic macrofaunal activity /." 2004. http://purl.galileo.usg.edu/uga%5Fetd/ding%5Fhaibing%5F200412%5Fphd.
Full textDirected by Ming-Yi Sun. Includes articles submitted to Geochimica et cosmochimica acta, and Limnology and oceanography, and an article accepted by Marine chemistry. Includes bibliographical references.
Mißbach, Helge. "Formation and preservation of abiotic organic signatures vs. lipid biomarkers—experimental studies in preparation for the ExoMars 2020 mission." Thesis, 2018. http://hdl.handle.net/11858/00-1735-0000-002E-E42A-7.
Full textRudolph, Maike. "Mobilisierung von Speicherlipiden in Cucumis sativus- und Arabodopsis thaliana-Keimlingen." Doctoral thesis, 2008. http://hdl.handle.net/11858/00-1735-0000-0006-B653-9.
Full textWU, Jong-Che, and 吳榮哲. "Anaerobic Biotechnology for Domestic Wastewater Treatment—Explore the Degradation of Sugars, Proteins and Lipids." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/pa2am3.
Full text國立臺灣大學
環境工程學研究所
107
This research, the fixed anaerobic biological treatment module was used to test the continuous influent of the whole domestic wastewater. The operating temperature was set to 25 °C, and the results were analyzed in four phases of hydraulic retention time (HRT) at 16, 12, 8 and 6 hours. The results showed that the total average removal rate of chemical oxygen demand (TCOD) was 76.5% and for the average removal rate of each phase, the average removal rate at HRT of 16 hours was 75.5%, 76.3% at HRT of 12 hours, 78.7% at HRT of 8 hours and 74.6% at HRT of 6 hours. At HRT of 6 hours and the operating condition of sudden load increase, the average TCOD of effluent was 62 mg/L (maximum 77 mg/L and minimum 49 mg/L), which was consistent with the emission standards for chemical oxygen demand of the discharged water (COD, 100mg/L), showing the stability of the fixed anaerobic biological treatment system for sudden load increase and low hydraulic retention time (HRT) that satisfied the current demand of domestic wastewater treatment via the fixed anaerobic biological treatment system. Such system does not require continuous aeration and the production of waste sludge is extremely low, which conserves electricity and tremendously reduces the sludge disposal cost. The analytic results of major organic components in three types of domestic wastewater, such as sugars, proteins and lipids, showed that the reduction rate of sugars and proteins could achieve more than 80% under the operating condition of any hydraulic retention time, where the level of lipids could only be maintained between 40% and 60%. It was obvious that the removal efficiency of lipids was the limiting factor for the fixed anaerobic biological treatment system. The improvement to degradation efficiency of lipids in the co-degradation effect of sugars, proteins and lipids is the key issue to enhance the overall effectiveness of the fixed anaerobic biological treatment system.
Ramôa, Renata Filipa Esteves. "Use of yeasts as bioremediation agents: application to hydrocarbons and phenolic compounds degradation." Master's thesis, 2018. http://hdl.handle.net/1822/59255.
Full textLiquid effluents of petrochemical industry and olive oil processing (olive mill wastewater, OMW) are two examples of effluents contaminated with pollutant compounds, respectively hydrocarbons and phenolic compounds. Biodegradation strategies involving microorganisms to simultaneously degrade these pollutants and obtain high added-value products have become an interesting and environment friendly approach. This work address the study of the ability of ten yeast species to grow on hydrocarbons (hexadecane) and phenolic compounds (tyrosol, phenol and catechol) as sole carbon and energy source. After a preliminary screening in Petri plates and 96-well microplate, two yeast species demonstrated an extraordinary ability to grow on hexadecane 1 g·L-1 (Yarrowia lipolytica W29) and phenolic compounds 1 g·L-1 (Candida tropicalis ATCC 250). In Erlenmeyer flask experiments, it was observed that Y. lipolytica W29 was able to grow on hexadecane 10 g·L-1, hexadecene 7.5 g·L-1 and in a mixture with both hydrocarbons (5 g·L-1 of each one). The increase of oxygen transfer, by raising the ratio of the volumes of headspace and liquid medium in flasks, had a positive effect on cellular growth and metabolites production. In hexadecane-based medium, for example, yeast cells produced lipase (up to 1260 U·L-1) and accumulated microbial lipids (up to 15 %, w/w), demonstrating its ability to valorize effluents contaminated with hydrocarbons. As C. tropicalis shown high potential to grow in phenolic compounds, its ability to grow on undiluted OMW (supplemented and non-supplemented with YNB) and produce added-value compounds was tested in Erlenmeyer flasks. The increase of flask headspace clearly enhanced the cellular growth, but did not favor the intracellular lipids accumulation. By contrast, it was observed that nitrogen limitation led to an enhancement of microbial lipids content: 39 % (w/w) and 24 % (w/w) of lipids were accumulated, respectively, in non-supplemented OMW medium and in repeated batch culture (pulses of OMW without YNB). Microbial lipids accumulated both by Y. lipolytica and C. tropicalis were mainly composed by oleic and linoleic acids and the unsaturated fraction exceeded the saturated one. The composition of these lipids, similar to that of common vegetable oils, makes them a potential feedstock for biodiesel production.
Os efluentes líquidos da indústria petroquímica e do processamento do azeite (águas ruças) são dois exemplos de efluentes contaminados com compostos poluentes, respetivamente hidrocarbonetos e compostos fenólicos. A biodegradação destes por microrganismos, obtendo simultaneamente compostos de alto valor acrescentado, tem-se tornado uma abordagem interessante e amiga do ambiente. Este trabalho aborda o estudo da capacidade de 10 espécies de leveduras para crescerem em hidrocarbonetos (hexadecano) e compostos fenólicos (tirosol, fenol e catecol) como única fonte de carbono e energia. Os ensaios preliminares em placa de Petri e microplaca demonstraram que Yarrowia lipolytica W29 crescia bem em 1 g·L-1 de hexadecano e Candida tropicalis ATCC 250 era capaz de crescer em 1 g·L-1 de cada composto fenólico. Nos ensaios realizados em frascos Erlenmeyer, Y. lipolytica W29 conseguiu crescer na presença de 10 g·L-1 de hexadecano, 7.5 g·L-1 de hexadeceno e numa mistura dos dois (5 g·L-1 de cada hidrocarboneto). O aumento da transferência de oxigénio, por aumento da razão do volume de headspace e do meio líquido dos frascos, teve um efeito positivo no crescimento e na produção de metabolitos. No meio com hexadecano, as células produziram lipase (1260 U·L-1) e acumularam lípidos intracelularmente (15 %, p/p), demonstrando o seu potencial para valorizar efluentes contaminados com hidrocarbonetos. Como a levedura C. tropicalis demonstrou potencial para crescer em compostos fenólicos, foi testada em frascos Erlenmeyer a sua capacidade para crescer em águas ruças não diluídas (com e sem suplementação com YNB) e produzir metabolitos de interesse. O aumento do volume do frasco levou ao aumento do crescimento celular, mas não favoreceu a acumulação de lípidos. Foi também observado que a limitação de azoto favorecia a acumulação de lípidos: no meio não suplementado com YNB obteve-se um conteúdo de lípidos igual a 39 % (p/p) e nos ensaios realizados em culturas descontínuas repetidas (pulsos de águas ruças sem YNB) obteve-se 24 % (p/p) de lípidos microbianos. Os lípidos microbianos acumulados por Y. lipolytica e C. tropicalis eram compostos maioritariamente por ácidos oleico e linoleico, e a fração insaturada era maior que a saturada. A composição destes lípidos microbianos, semelhante à dos óleos vegetais comuns, torna-os uma potencial matéria-prima para a produção de biodiesel.